High-purity elemental silicon is used in the manufacture of electronic semiconductors and solar cells. Various methods have been used for the production of high-purity silicon. For example, the Siemens process is a well-known method for the production of elemental silicon from trichlorosilane. However, the process is highly energy-consuming and creates three to four moles of silicon tetrachloride by-product for every mole of obtained silicon.
Improvements have been made to the original Siemens process. For example, the process disclosed in U.S. Pat. No. 6,932,954 is reported to diminish the amount of silicon tetrachloride by-product formed during pyrolysis of trichlorosilane by conducting the pyrolysis at a higher temperature. However, the amount of silicon tetrachloride produced is still one-third to one-half that produced under the original Siemens process conditions. The silicon tetrachloride by-product that is formed is reduced back to trichlorosilane, which is re-introduced into the system.
A need exists for an even more efficient process for the production of high-purity silicon. The invention described herein provides such a method. This and other advantages of the invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.